Retropatellar Accessory Portals for Improved Access to the Patella: Anatomic Description and Evaluation of Safety

BACKGROUND: Standard knee arthroscopy portals are frequently used to address retropatellar chondral pathology. Alternative portals may offer a safe and simple substitute, particularly when reaching the base of deep lesions is required. PURPOSE: To describe and assess the safety of accessory retropatellar portals. STUDY DESIGN: Descriptive laboratory study. METHODS: An anatomic study was performed on 10 fresh-frozen cadaveric knees. Medial and lateral retropatellar portals were created, and the distance to adjacent neurovascular structures (common peroneal nerve [CPN] and infrapatellar branch of the saphenous nerve [IPBSN]) and bony landmarks (medial and lateral epicondyles and margins of the midpatella) was recorded. A clinical account of portal use is provided through a retrospective chart review. RESULTS: The medial and lateral retropatellar portals were a mean 15.8 ± 15.5 mm and 53.8 ± 7.2 mm from the IPBSN and CPN, respectively. No nerves were contacted in any specimens. Clinically, the portals have been used in 109 cases over a 7-year period without complication. CONCLUSION: The high level of IPBSN variability poses some risk to medial portal use; however, there is little to no risk laterally. Clinical experience with portals suggests that they can be used safely. We recommend careful blunt dissection to minimize chance of iatrogenic nerve injury. CLINICAL RELEVANCE: Retropatellar portals may offer improved access to chondral lesions of the patella, thereby safely allowing one to maintain an arthroscopic approach.